1. Field of the Invention
The present invention relates to copper alloys, and more particularly to copper alloys which are useful in the fabrication of fins for automobile radiators.
2. Description of the Prior Art
The fins on automobile radiators are conventionally made of metallic materials which display high heat resistance, high thermal conductivity, high strength and high workability. With respect to the need that the metallic materials forming the fins display high heat resistance, this is in part due to the fact that the fins must be able to resist softening when they soldered to the radiator.
Over the past decade it has become increasingly important to automobile manufacturers to produce vehicles having reduced weights, and as a result manufacturers have sought ways to reduce the weights of the parts making up the automobiles, including the radiators therein. At the same time, it is desirable that the fins on the radiator provide an improved heat dissipating capacity per unit volume. In this regard, it has been considered desirable that the fins of automobile radiators be made of a material having a thermal conductivity of, say, at least 95%. IACS in terms of electrical conductivity, and a sufficient heat resistance to give a Vickers hardness of at least 110 after being heated at 350.degree. C. for five minutes.
Copper alloys have previously been used (or proposed for use) in making radiator fins, these alloys containing a few percent of one or two elements selected from the group of tin, phosphorus, nickel, silver, cadmium, manganese and zinc. See, for example, the book by Allison Butts entitle "Copper, The Science & Technology of the Metal, Its Alloys and Compounds," Reinhold Publishing Corporation, New York (1954). On the other hand, copper alloys made of electrolytic copper and containing 0.01 to 0.08% by weight of tellurium are disclosed in Japanese Patent Publication No. 1706/1957, published on Mar. 15, 1957, and a copper alloy made of electrolytic copper and containing 0.03 to 1.0%, by weight of tellurium is disclosed in Japanese Patent Publication No. 5818/1976, published on Feb. 23, 1976. None of these alloys, however, display sufficient thermal conductivities and heat resistances to be useful in making radiator fins.
An object of the present invention is to provide a copper alloy which, when used to make radiator fins, will provide the fins with optimum physical properties, including high thermal conductivity and high heat resistance.